Information
-
Patent Grant
-
6195958
-
Patent Number
6,195,958
-
Date Filed
Tuesday, March 31, 199826 years ago
-
Date Issued
Tuesday, March 6, 200123 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Friedman; Carl D.
- Horton; Yvonne M.
Agents
- Eckert; Inger H.
- Barns; Stephen W.
-
CPC
-
US Classifications
Field of Search
US
- 052 4041
- 052 4071
- 052 4074
- 052 4075
- 052 478
- 052 4831
- 052 74912
- 052 74611
- 242 546
- 242 548
- 242 557
- 242 592
- 242 5985
- 242 610
- 270 3011
- 270 3013
-
International Classifications
-
Abstract
An apparatus for propelling a carriage along a roof structure of the type having a plurality of purlins spaced apart from one another in a parallel arrangement, and method of using same are disclosed. The apparatus includes a carriage movable along the length of the purlins for dispensing a support sheet from a roll for support of insulation material as the carriage travels along the length of the purlins so that the support sheet depends from the top portion of adjacent purlins. The apparatus further includes a puller assembly attached to the carriage. The puller assembly includes a driven wheel frictionally engaged with a surface a purlin, and a drive mechanism for rotating the driven wheel.
Description
TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION
This invention relates to the construction of an insulated metal roof structure for use in commercial and industrial buildings.
BACKGROUND OF THE INVENTION
Metal roof structures typically comprise a series of parallel rafter beams extending across the building in one direction and purlin beams parallel to each other mounted on top of the rafters extending in a direction normal to the rafters. Insulation is material in long sheets is placed in the area between purlins. The sheets of insulation material can be laid along the length of the purlins or across the purlins in a direction normal to the purlins. If desired, the roof structure can have a first layer of insulation material which is laid along the length of the purlins, and a second layer of insulation material which is laid laterally across the purlins on top of the first layer on insulation. Hard roofing material such as metal decking is then attached on top of the purlins over the insulation material. Because the hard roofing material comes in long sheets and the roofs generally have two sloped sections, it is customary to construct the roof along the length of the structure from one end to the other. The workers stand on the previously laid section of roof to construct the next section.
The insulation material is supported between the purlins beneath the hard roofing material. Various methods of supporting the insulation material have been used. Mounting straps or wire mesh which are attached to or draped over the purlins forming a lattice have been used. This is referred to as banding. A sheet, typically made of vinyl and acting as a vapor barrier, is then rolled onto the lattice, and insulation material is placed between adjacent purlins and over the sheet. If the installation of the lattice is done from underneath the roof structure, scaffolding or lifting equipment is typically required for installation. Since the lattice encompasses the entire roof, installation is costly and time consuming. Once the hard roofing material is mounted on the purlins, the sheet can support the insulation material and the lattice no longer serves any useful purpose.
Some systems dispense with the lattice and use the sheet itself to support the insulation material. The support sheet is dispensed from a roll and draped from adjacent purlins. Insulation material is then placed on top of the support sheet. A carriage has been used to aid in the dispensing of the support sheet, such as that disclosed in U.S. Pat. No. 4,967,535 to Alderman. The carriage is positioned on top of the purlins and travels the length of the purlins during the roof construction. A roll of the support sheet material is mounted on the carriage and the support sheet is dispensed from the roll and placed on top of the purlins. As the carriage travels the length of the purlins, the support sheet is draped across the purlins.
The carriage can be any length up to the width of the roof itself. For example, the carriage can be comprised of a plurality of carriage sections which are joined together so that they span the entire width of the roof. Each carriage section has a roll of support sheet dispensing the support sheet across two adjacent purlins. The carriage is then propelled along the length of the purlins so that the carriage sections move in unison.
In the past, the carriage was manually pushed across the roof along the length of the purlins by means of push rods. The workers standing on a completed section of the roof structure would manually push the carriage to the desired position. Another method of advancing the carriage was by pulling the carriage across the roof by means of a relatively long cable and large winch fastened to the carriage. The cable was typically 200 feet long and had a conventional hook attached at the end of the cable. The cable was reeled out from the spool of the winch and then hooked to a flange of a rafter beam. If the roof structure was longer than 200 feet, the cable was attached to the farthest rafter beam which the cable was able to reach. The winch was then manually operated to take up the cable about the spool of the winch so as to advance the carriage. It was preferred that the cable be as long as possible, so that the cable did not have to be re-attached to a different rafter beam often. Because the winch is attached to the carriage and moves over and across the rafter beams, the cable is laid across the tops of all the rafter beams between the carriage and the end of the roof structure. However, it can be difficult and time consuming to unroll the cable and pull the end of the cable across the rafter beams 200 feet away from the carriage. It is also difficult to initially attach the hook at the end of the roof structure since this requires a worker to climb to the top of the end of the roof structure. Since the cable is relatively long, the cable is relatively heavy and awkward to handle. Also, the size of the winch is relatively large and heavy to accommodate the length of the cable required to span across the roof structure.
It would be desirable to have an apparatus and method for moving the carriage along the length of the purlins which is relatively simple, fast, and safe to perform.
SUMMARY OF THE INVENTION
The above objects as well as other objects not specifically enumerated are achieved by an apparatus and a method of using the same for propelling a carriage along a roof structure. The apparatus and method provides for a relatively simple and fast system for moving the carriage.
The apparatus of the present invention provides for a roof structure of the type having a plurality of purlins spaced apart from one another in a parallel arrangement. The apparatus includes a carriage movable along the length of the purlins for dispensing a support sheet from a roll for support of insulation material as the carriage travels along the length of the purlins so that the support sheet depends from the top portion of adjacent purlins. The apparatus further includes a puller assembly attached to the carriage. The puller assembly includes a driven wheel frictionally engaged with a surface of a purlin, and a drive mechanism for rotating the driven wheel.
The method of the present invention includes first providing a carriage upon which is mounted a roll of support sheet, wherein the support sheet has side edges which are generally aligned with the top portions of adjacent purlins so that the support sheet can depend from the adjacent purlins. A puller assembly is also provided for rotating a driven wheel. The puller assembly is attached to the carriage. The driven wheel is then positioned adjacent a purlin for frictional engagement therewith. Next, the puller assembly is actuated to rotate the driven wheel so that the driven wheel rolls along the length of the purlin, thereby propelling the carriage along the purlins.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a schematic elevational side view of a carriage and a first embodiment of a puller assembly, in accordance with the present invention, on top of a roof structure.
FIG. 2
is a schematic sectional view taken along Lines
2
—
2
of
FIG. 1
illustrating a completed section of the insulated roof structure.
FIG. 3
is a schematic elevational view illustrating a first embodiment of a driving configuration between a pair of wheels engaged with a purlin.
FIG. 4
is a schematic elevational view illustrating a second embodiment of a driving configuration between a pair of wheels and a purlin.
FIG. 5
is a schematic elevational view illustrating a third embodiment of a driving configuration between a pair of wheels and a purlin.
FIG. 6
is an elevational side view of the puller assembly of
FIG. 1
FIG. 7
is a partial sectional view of the puller assembly taken along Lines
7
—
7
of FIG.
6
.
FIG. 8
is a partial sectional view of the puller assembly taken along Lines
8
—
8
of FIG.
6
.
FIG. 9
is a partial sectional view of the puller assembly taken along Lines
9
—
9
of FIG.
8
.
FIG. 10
is a partial sectional view of the puller assembly taken along Lines
10
—
10
of FIG.
8
.
FIG. 11
is a partial sectional view of second embodiment of a puller assembly, in accordance with the present invention.
FIG. 12
is a partial sectional view of the puller assembly taken along Lines
12
—
12
of FIG.
11
.
DE
TAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION Referring to
FIGS. 1 and 2
, there is illustrated a partially completed building roof structure, indicated generally at
10
. The roof structure is supported by a building framework which includes main rafter beams
12
positioned parallel to each other. A plurality of purlins
18
, spaced apart and arranged parallel to each other, is fastened on top of the rafters in a direction normal to the rafters. The building framework may have two sloped sections (not shown) which are joined together to form a peak. The sloped roof sides generally provide for rain and snow drainage. The spacing of the rafter beams is typically within the range of from about 25 to about 30 feet (7.6 to about 9.1 meters) on centers. The spacing of the purlins is typically about 5 feet (1.52 m) on centers. As best shown in
FIG. 2
, the purlins typically have a generally Z-shaped cross-section, and include a horizontally extending upper portion
20
, a vertically extending web
22
, and a horizontally extending lower portion
24
. Of course, roof structures may also be constructed from bar joists or trusses, and the invention as described herein will work equally well with purlins, bar joists or trusses. The use of the term “purlins” in this specification and claims includes not only traditional purlins, but also joists, trusses, and other similar structural members.
Broadly stated, the roof structure is constructed by use of a carriage, indicated generally at
26
, which rides on the upper portion
20
of the purlins and travels along the length of the purlins in a downstream direction, represented by an arrow
28
, as shown in FIG.
1
. Preferably, the carriage has rollers
30
, rotatably mounted on the carriage, which roll along the upper portions of the purlins. As the carriage is moved, a support sheet
32
is payed out from a roll
34
. The support sheet is draped on top of adjacent purlins so that the support sheet depends from the upper portion of the purlins, as shown in FIG.
2
. The support sheet supports a layer of insulation material
36
which is placed on top of the support sheet between the adjacent purlins. The insulation material is typically dispensed from a roll
38
but can be applied by any suitable manner, such as by applying insulation batts on top of the support sheet. Alternatively, a layer of insulation may be placed laterally across the purlins. After the insulation material has been placed on the support sheet, long sheets of hard roofing material
40
, such as metal roof decking, are then attached to the upper portion of the purlins over the support sheet and insulation. The hard roofing material can be fastened to the purlins in any suitable manner, such as by threaded fasteners or clips. The attachment of the hard roofing material presses down on the edges of the support sheet which are sandwiched between the upper portion
20
of the purlins and the hard roofing material
40
, so that the support sheet supports the insulation between the purlins.
Because the hard roofing material comes in long sheets, typically 30 to 35 feet (9.1 to 10.7 m), and the roofs generally have two sloped roof sides, it is customary to construct a first section of the roof structure along the width of the sloped roof side and then proceed along the length of the structure from one end to the other. The workers stand on the previously attached first section of the roof structure to assemble the next section of roof. The carriage travels along the length of the purlins and is moved by the workers as each new section of roof is assembled.
The carriage can be any length up to the width of the roof itself. Preferably, the carriage is comprised of a plurality of carriage sections which can be joined together so that they span the entire width of the sloped section of the roof. The carriage is then propelled across the purlins, as will be discussed in detail below, in the downstream direction
28
so that all the carriage sections move in unison. Because the support sheet is draped across the upper portion of adjacent purlins, the total width of the support sheet is wider than the distance between the purlins. Therefore, adjacent support sheet rolls are not co-linear and must be slightly staggered. Typically, a carriage section covers two purlin spans, i.e., about 10 feet (3.3 m) in length. Therefore, each carriage section preferably has both a leading roll
34
and a trailing roll
42
of insulation support sheet, one roll for each of two adjacent purlin spans. The edge of the support sheet from the trailing roll
42
will be draped on top of the edge of the support sheet from the leading roll
34
as the carriage moves in the downstream direction. Multiple identical carriage sections having a leading and trailing roll can, therefore, be joined together, with every roll being staggered from an adjacent roll.
The carriage
26
can be any suitable apparatus which moves along the top of the purlins and dispenses the support sheet. As seen from
FIG. 1
, the carriage preferably includes safety handrails
44
and a deck
46
for the worker to stand on while operating or moving the carriage. The rollers
30
are mounted from the deck
46
of the carriage. Preferably, the carriage is equipped with two rollers (front and rear) for each purlin, as shown in FIG.
1
. The carriage also includes a framework
48
for mounting the rolls
34
and
42
. Mounted on the framework are turning bars
50
which extend laterally across associated support sheets and are positioned slightly above the upper portions
20
of the purlins
18
so as to direct the support sheet to a generally horizontal position.
Attached to the carriage is an optional plate
52
which extends from the carriage in an upstream direction opposite the downstream direction
28
. The plate supports the payed out portion of the support sheet and insulation material so that the support sheet does not drape downwardly, thereby pulling the longitudinal edges of the support sheet off the upper portion of the purlins. If sufficiently built, the plate can be used for fall protection for the workers to prevent them from falling off the leading edge of the previously completed section of roof. The plate can be attached to the carriage by any suitable means. The plate follows the carriage as the carriage moves along the length of the purlins. Preferably, the plate has wheels
54
which also support the plate by rolling along the upper portion
20
of the purlins
18
. However, it is not required that the payed out support sheet be supported by the plate. The carriage could be modified so that the support sheet is payed out in such a manner that the support sheet is underneath the plate. If desired, the roll
38
of insulation material
36
could be positioned on the plate
52
above the support sheet. Generally, the plate is located in a gap
56
which exists between the completed section of the roof structure
10
and the carriage
26
. The plate hinders wind from blowing vertically through the gap
56
and therefore, the wind does not disturb the insulation material
36
and the support sheet
32
.
The space between the vertical webs
22
of adjacent purlins
18
generally defines an insulation cavity
58
, as shown in FIG.
2
. The insulation cavity has a generally rectangular cross-sectional shape. It is advantageous to fill out the insulation cavity uniformly with the insulation material without leaving relatively large gaps, thereby maximizing the insulating qualities of the roof structure. The purpose of the support sheet is to support the insulation material in the insulation cavity, but the support sheet can also be used as a vapor barrier, and for aesthetic purposes. The support sheet can be of any suitable material for the stated purposes, such as vinyl or foil faced paper.
The carriage
26
is propelled or advanced along the length of the purlins in the downstream direction
28
by a puller assembly, indicated generally at
60
, in accordance with the present invention. The puller assembly
60
can be any suitable apparatus which is attached to the carriage and includes a drive mechanism for rotating at least one driven wheel (not shown in
FIG. 2
) which frictionally engages a surface of a purlin. The rotation of the driven wheel causes the puller assembly and the attached carriage to move along the length of the purlins. Any suitable driving configuration between the driven wheel and the purlin can be used. A plurality of puller assemblies may be used to advance a relatively wide carriage, such as when a plurality of carriage sections are joined together.
For example, there is illustrated in
FIG. 3
a first embodiment of a driving configuration, indicated generally at
61
, between a pair of wheels
62
and
64
engaging a purlin
18
. The wheel
62
rotates about an axis
66
. The wheel
64
rotates about an axis
68
. The wheels
62
and
64
are positioned on opposing sides of the upper portion
20
of the purlin so that the purlin is sandwiched or pinched between the wheels
62
and
64
. The wheels
62
and
64
are in frictional engagement with surfaces
70
and
72
, respectively, of the upper portion of the pirlin such that there is substantially no slippage between the surface of the wheels
62
and
64
and the respective surfaces of the purlin. Preferably, the wheels
62
and
64
are biased in a direction towards one another to assist in maintaining a frictional engagement between the surfaces of the wheels and the respective surfaces of the purlin. The driving configuration
61
can be arranged so that the wheel
62
is the driven wheel, the wheel
64
is the driven wheel, or both of the wheels
62
and
64
are driven wheels. Alternatively, the wheel
64
can be eliminated, wherein the weight of the structure above the wheel
62
assists in maintaining a frictional engagement between the surface of the wheel
62
and the surface
70
of the upper portion of the purlin.
In another example, there is shove in
FIG. 4
a second embodiment of a driving configuration, indicated generally at
74
, which is similar to the driving configuration
61
of
FIG. 3
, with the exception that the driving configuration
74
has a pair of wheels
76
frictionally engaging the vertical web
22
of the purlin
18
. In yet another example, there is shown in
FIG. 5
a third embodiment of a driving configuration, indicated generally at
80
, which is similar to the driving configuration
61
of FIG.
3
. The driving configuration
80
has a wheel
82
which is frictionally engaged with a top portion
84
of the vertical web
22
, and a wheel
86
which is frictionally engaged with an edge
88
of the upper portion
20
of the purlin.
Referring to
FIGS. 6 through 10
, the puller assembly
60
generally includes a drive mechanism, such as a motor
90
, and a main body, indicated generally at
92
. The motor is attached to the main body by a mounting bracket
94
. Actuation of the motor rotates an output shaft
96
. The motor can be energized by any suitable power device, such as a generator or battery (not shown). Of course, the drive mechanism can be any suitable apparatus, such as a crank, for rotating the output shaft
96
.
The main body includes an upper plate
98
, a pair of side plates
100
and
102
, and a pair of end plates
104
and
106
. A pair of rollers
108
and
110
are rotatably mounted on the end plates
104
and
106
, respectively, by mounting brackets
112
and
114
. The rollers
108
and
110
roll along the upper portion
20
of the purlin
18
as the puller assembly
60
moves along the length of the purlin. A pair of cable attachments
116
and
118
are fastened to the upper plate
98
. One end of a cable
120
is fastened to the cable attachment
118
while the other end of the cable
120
is attached to the carriage
26
, as shown in
FIG. 1
, thereby attaching the carriage to the puller assembly. Note that the cable attachment
116
is used when the puller assembly is oriented
180
degrees about the purlin.
As best seen in
FIG. 7
, the puller assembly further includes a driven wheel assembly, indicated generally at
122
. The driven wheel assembly includes three driven wheels
124
oriented in a manner similar to the wheel
86
in FIG.
5
. Each driven wheel includes a shaft
126
extending through holes
128
formed through a ledge
130
. The ledge
130
is attached to the side plate
100
and the end plates
104
and
106
. Attached to each shaft is a large diameter portion
132
and a small diameter portion
134
positioned underneath the ledge
130
. The large diameter portion
132
and the small diameter portion
134
are positioned adjacent each other, defining a shoulder
136
. Each driven wheel further includes a spacer
138
and a gear
140
positioned above the ledge
130
. The spacer and the gear are attached to the respective shafts
126
for rotation therewith. Each driven wheel is biased in an upward direction, as viewing
FIG. 7
, by a spring
142
acting against a washer
144
. The washers
144
are attached to their respective shafts. Preferably, the shaft
126
of a centrally located driven wheel
124
a
is rotatably connected to the output shaft
96
of the motor
90
such that rotation of the output shaft rotates the shaft
126
while permitting a limited amount of axial movement therebetween. The springs of outwardly located driven wheels
124
b
are disposed in tubular spring retainers
146
.
The driven wheel assembly further includes a pair of idler gear assemblies
150
each having a gear
152
and a spacer
154
. The gears
152
are rotatably mounted about pins
156
attached to the upper plate
98
and the ledge
130
. The gears
152
are positioned between the gears
140
of the driven wheels
124
and are in meshed engagement therewith.
Referring now to
FIGS. 8 through 10
, the puller assembly further includes a non-driven assembly, indicated generally at
160
. The non-driven assembly
160
includes a housing block
162
slidably mounted on channel members
164
attached to the upper plate
98
. The housing block has grooves
166
formed therein which cooperate with flanges
168
formed in the channel members to provide the sliding mounting arrangement. The housing block is movable in a horizontal direction towards or away from the purlin. Three non-driven wheels
170
are rotatably mounted in the housing block by pins
172
fastened to the housing block. The non-driven wheels
170
are oriented in a similar manner to the wheel
82
in FIG.
5
. The term “non-driven driven wheels” is defined herein as wheels which are not operatively connected to the output shaft of the motor, but are rather free to rotate about their axes. The term “driven wheels” is defined herein as wheels which are operatively connected to the output shaft of the motor. Preferably, the housing block is biased in a direction towards the purlin, such as by a pair of spring assemblies
174
. The spring assemblies include a rod
176
having a threaded portion
178
threadably engaged with a threaded bore
180
formed in the side plate
102
. Each rod has an end
182
which is disposed in a respective bore
184
formed through the housing block. Snap rings
186
are fastened to the ends
182
to retain the housing block from moving beyond the end
182
of the rods. The spring assemblies further include washers
188
attached to the rods. Springs
190
are disposed around the rod and positioned between the washers
188
and the housing block. The springs bias the housing block, and the non-driven wheels
170
, against the vertical web
22
of the purlin
18
. The position of the rods can be adjusted by threadably advancing the rods with respect to the threaded bores
180
and then tightening lock nuts
192
to secure the position of the rods. By changing the position of the rods, the spring force acting against the housing block can be adjusted. Of course, any suitable locking mechanism, such as a clamp (not shown), can be used to position the rods.
As best shown in
FIG. 9
, the puller assembly
60
has a driving configuration similar to the driving configuration
80
, illustrated in FIG.
5
. The non-driven wheels
170
are frictionally engaged with the top portion
84
of the vertical web
22
of the purlin. The driven wheels
124
are frictionally engaged with the edge
88
of the purlin
18
such that the edge
88
is adjacent the shoulder
136
. Specifically, the pressing of the small diameter portion
134
against the edge
88
of the purlin drives the puller assembly and carriage along the purlins. Thus, the rollers
110
and the shoulders
136
of the driven wheels
124
cooperate to fix the vertical position of the puller assembly with respect to the purlin, as represented by an arrow
200
in FIG.
9
. However, the springs
142
permit limited movement of the driven wheels
124
in the vertical direction to overcome obstacles encountered as the puller assembly moves along the length of the purlins. Also, the small diameter portions
134
of the driven wheels
124
cooperate with the non-driven wheels
170
to fix the position of the puller assembly with respect to the purlin in the horizontal direction, represented by an arrow
202
in FIG.
9
. The spring assemblies
174
permit limited movement of the non-driven wheels
170
in the horizontal direction
202
.
To propel the carriage in the downstream direction
28
, the motor
90
is energized to rotate the output shaft
96
in a clockwise direction, as viewing FIG.
8
. The output shaft imparts a clockwise rotation on the gears
140
of the driven wheels
124
. Note that the idler gears
152
will rotate in a counterclockwise direction thereby imparting a clockwise rotation on the gears
140
. Rotation of the driven wheels
124
will propel the puller assembly in the downstream direction along the length of the purlins, thereby pulling the carriage
26
.
A logic circuit (not shown) may be incorporated into the controls of the motor
90
so that the motor is operated for a predetermined amount of time. Thus, a worker can depress a single switch which operates the motor to rotate the driven wheels
124
as described above, for a predetermined amount of time corresponding to a selected distance of movement of the carriage. The logic circuit would enable the carriage to be moved, for example, by a distance approximately equal to the width of the sheets of the hard roofing material
40
.
To provide a high frictional engagement between the surfaces of the driven wheels
124
, the surfaces of the non-driven wheels
170
, and the surfaces of the purlin, the surfaces of the small diameter portion
134
of the driven wheels
124
and/or the non-driven wheels
170
can be made of an elastomeric material, such as rubber. Alternatively, the surfaces of the driven wheels and/or the surfaces of the non-driven wheels can be knurled or textured in some other manner.
Although the puller assembly
60
is shown and described as being attached to the carriage
26
by the cable
120
, it should be understood that the puller assembly could be attached by any other suitable means, or could be mounted on the carriage. Although the wheels
170
are described alone as being non-driven, it is to be understood that they could also be driven.
There is illustrated in
FIGS. 11 and 12
, a second embodiment of a puller assembly, indicated generally at
210
. The puller assembly
210
is similar in structure and function to the puller assembly
60
of
FIGS. 1 through 10
, with the exception that the puller assembly
210
is configured to move along a bar joist
212
generally having an I-shaped cross-section. The bar joist has a horizontally extending upper flange
214
and a horizontally extending lower flange
216
separated by rods
218
. The puller assembly
210
includes a housing block
220
having a slot
222
formed therein. Three non-driven wheels
224
are rotatably mounted in the slot of the housing. The righthand edge of the upper flange
214
, as viewing
FIG. 12
, is disposed within the slot
222
and engages the non-driven wheels
224
.
The principle and mode of operation of this invention have been described in its preferred embodiments. However, it should be noted that this invention may be practiced otherwise than as specifically illustrated and described without departing from its scope.
Claims
- 1. An apparatus movable along a roof structure having a plurality of purlins spaced apart from one another in a parallel arrangement, the apparatus comprising:a carriage movable along the length of the purlins for dispensing a support sheet from a roll for support of insulation material as the carriage travels along the length of the purlins so that the support sheet depends from the top portion of adjacent purlins; and a puller assembly attached to the carriage, the puller assembly including: a driven wheel adapted to frictionally engage the surface of a purlin; a drive mechanism for rotating the driven wheel; and a non-driven wheel frictionally engaged with a surface of the purlin, such that the driven wheel and the non-driven wheel are positioned on opposing sides of the purlin.
- 2. The apparatus of claim 1 further including a second wheel frictionally engaged with another surface of the purlin, wherein the driven wheel and the second wheel are positioned on opposing sides of the purlin.
- 3. The apparatus of claim 2, wherein the driven wheel and the second wheel are biased in a direction towards one another by a spring.
- 4. The apparatus of claim 3, wherein the position of the spring is adjustable to change the spring force acting on the driven wheel and the second wheel.
- 5. The apparatus of claim 2, wherein the driven wheel and the second wheel are mounted for movement in a direction towards and away from each other.
- 6. The apparatus of claim 2, wherein the second wheel is connected to the drive mechanism for rotation thereby.
- 7. The apparatus of claim 1, wherein the driven wheel has a surface made of an elastomeric material to frictionally engage the surface of the purlin.
- 8. The apparatus of claim 1, wherein the driven wheel has a knurled surface to frictionally engage the surface of the purlin.
- 9. The apparatus of claim 1, wherein the driven wheel includes a first diameter portion and second diameter portion which is larger than the first diameter portion, the first and second diameter portions being adjacent to each other forming a shoulder.
- 10. The apparatus of claim 1, wherein the driven wheel is mounted for rotation on an axis, and wherein the driven wheel is mounted for movement in a direction parallel to the axis.
- 11. The apparatus of claim 1, wherein the drive mechanism includes a motor.
- 12. The apparatus of claim 11, wherein the drive mechanism includes a logic circuit which is actuated by a single switch such that upon actuation of the switch, the logic circuit operates the motor for a predetermined amount of time.
- 13. The apparatus of claim 1, wherein the puller assembly has a roller which rolls along an upper portion of the purlin as the carriage moves along the length of the purlins.
- 14. The apparatus of claim 1, wherein the puller assembly is attached to the carriage by a cable.
- 15. An apparatus movable along a roof structure having a plurality of purlins spaced apart from one another in a parallel arrangement, the apparatus comprising:a carriage movable along the length of the purlins for dispensing a support sheet from a roll for support of insulation material as the carriage travels along the length of the purlins so that the support sheet depends from the top portion of adjacent purlins; and a puller assembly attached to the carriage, the puller assembly including: a plurality of driven wheels frictionally engaged with a surface of a purlin; a drive mechanism for rotating the driven wheel; and a plurality of non-driven wheels frictionally engaged with a surface of the purlin, such that the driven wheels and the non-driven wheels are positioned on opposing sides of the purlin.
- 16. The apparatus of claim 15, wherein the plurality of driven wheels and the plurality of non-driven wheels are biased in a direction towards one another by a spring.
- 17. A method of propelling a carriage along a plurality of purlins, the method comprising the steps of:a. providing a carriage upon which is mounted a roll of support sheet, wherein the support sheet has side edges which are generally aligned with the top portions of adjacent purlins so that the support sheet can depend from the adjacent purlins; b. providing a puller assembly for rotating a driven wheel, the puller assembly being attached to the carriage; c. positioning the driven wheel adjacent a purlin for frictional engagement therewith; d. actuating the puller assembly to rotate the driven wheel so that the driven wheel rolls along the length of the purlin, thereby propelling the carriage along the purlins.
- 18. The method of claim 17 including the step of positioning a non-driven wheel on the opposing side of the purlin for frictional engagement therewith.
- 19. The method of claim 18, wherein the driven wheel and the non-driven wheel are biased in a direction towards one another by a spring.
- 20. The method of claim 19, wherein the spring force acting on the driven wheel and the non-driven wheel is adjutable.
US Referenced Citations (9)